Nail psoriasis has variable prevalence and heterogeneous aspects. Many of them could mimic onychomycosis (OM). It has been suggested that patients with nail psoriasis are at high risk of OM. The aim of our study was to determine the epidemiological and clinical characteristics of nail psoriasis and to estimate the frequency and the factors associated with OM in psoriatic patients. The studied group included 163 patients with psoriasis aged 18 years or older. Epidemiological and clinical data, as well as the severity of skin and nails disease by evaluating the Psoriasis Area Severity Index (PASI) and Nail Area Psoriasis Severity Index (NAPSI) scores were specified. Mycological testing was performed for patients with nail alterations. Nail involvement was found in 71.2% of patients. The most common nail alterations were subungual hyperkeratosis and onycholysis. The mean NAPSI score was 11.6. Mycological testing was performed in 104 patients with onychodystrophy. OM was diagnosed in 53% of the cases. Dermatophytes were the most isolated pathogens. OM was associated with male gender, but not with age, NAPSI, or PASI score. Psoriasis is one of the dermatoses that most commonly affect the nail. Available data about the association between nail psoriasis and OM are controversial. However, mycological testing should be routinely performed on psoriatic nails.

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Verrucous carcinoma (VC) of the nail bed is a rare variant of squamous cell carcinoma that is often misdiagnosed as a benign condition. The clinical presentation of this tumor is very similar to that of warts or onychomycosis hence the delayed appropriate treatment. Its association with human papillomavirus (HPV) infection has rarely been reported. The treatment of VC of the nail unit depends on the extent of the lesion and the presence or the absence of bone. We here report an unusual case of VC of the nail bed of the left big toe in a man associated with HPV53 infection that had been mistaken for a wart for 1 year. The condition was treated by ray amputation.

SARS‐CoV‐2, the virus that causes coronavirus disease 2019 (COVID‐19), is associated with flares of psoriasis in patients with well‐documented disease. Both viral infection and medications used for treatment, like hydroxychloroquine, were incriminated. Herein, we report the case of a 25‐year‐old male patient who presented a first‐onset guttate psoriasis following a COVID‐19 infection. We have not found previous descriptions of de novo guttate psoriasis post‐COVID‐19.

Onychomatricoma (OM) is a rare benign tumour of the nail matrix characterized by specific clinical and histologic features. The main clinical signs are thickening of the nail plate, xanthonychia, overcurvature of the nail plate, and multiple splinter haemorrhages. The diagnosis is based on clinical, radiological and histopathological findings. Histologically, the tumour is characterized by filiform epithelial projections. The objective of this study is to present the first reported Tunisian case of OM, focusing on the contribution of magnetic resonance imaging to the diagnosis of OM. A review on the subject is also presented.